Data Sources
Every number on Master Converters comes from somewhere. This page lists exactly where — which standards we follow, which APIs we use, and what runs locally with no external data at all.
Maintained by:The Master Converters Team | Last reviewed: July 2026
Unit Conversion Standards
Where our conversion factors come from.
SI Units (Metric)
International System of Units — maintained by the International Bureau of Weights and Measures (BIPM). Used for length, weight, volume, area, speed, pressure, energy, power, temperature, and more.
NIST Handbook 44
U.S. National Institute of Standards and Technology specifications for weights and measures. Used as a cross-reference for US customary unit factors.
ISO Standards
International Organization for Standardization standards for specific categories like paper sizes (ISO 216), date/time (ISO 8601), and currency codes (ISO 4217).
Category-Specific Sources
Clothing sizes, shoe sizes, and cooking measurements use regional charts from manufacturers, fashion industry standards, and culinary references.
Live Cryptocurrency Data
Real-time and near-real-time crypto prices.
CoinGecko API
Free public market data API providing prices for Bitcoin (BTC), Polkadot (DOT), and other cryptocurrencies. Data is aggregated from multiple exchanges. Refresh interval: approximately every 60 seconds.
Price Display
Each live market tool shows the provider name, the timestamp of the last price update, and any provider-specific error states (rate limiting, downtime, etc.).
Limitations
Prices may be delayed by 30–90 seconds depending on the API. Prices reflect a market average and may differ from individual exchange prices. Not suitable for real-time trading decisions.
Gold & Precious Metals
Live spot prices for gold and metals.
Gold API
Public XAU (gold) price data. Provides spot prices in USD and other fiat currencies. Data is refreshed when a gold tool is opened.
Display Standards
Gold prices are displayed per troy ounce (XAU) as per international convention. The tool page shows the timestamp and source attribution.
Limitations
Spot prices are reference values and may differ from dealer or retail prices. Prices do not include premiums, taxes, or shipping costs.
Currency Exchange Rates
Fiat currency conversion rates.
Exchange Rate Providers
Currency tools fetch mid-market exchange rates from public data providers. Rates are indicative and may differ from bank or remittance service rates.
Refresh Frequency
Exchange rates are typically updated daily for major currency pairs. The tool page displays the last-updated timestamp.
Limitations
Not suitable for financial transactions. Mid-market rates do not include bank spreads, fees, or commissions. For actual transfers, check with your bank or payment provider.
Browser-Side Tools (No External Data)
Tools that run entirely on your device with no external API calls.
Hash Generators
MD5, SHA-1, SHA-256, SHA-512, and other hash functions use browser-native Web Crypto API or JavaScript implementations. No data is sent to a server.
Text & Writing Tools
Word counter, readability checker, case converter, text compare, and other text utilities process content locally in your browser.
PDF Tools
Supported PDF actions (compress, rotate, watermark, page numbers) use browser-side JavaScript libraries. Files stay on your device.
Developer Tools
JSON formatter, Base64 encoder/decoder, URL encoder, JWT decoder, regex tester, and other dev utilities process data locally.
SEO & Marketing Tools
Meta checker, SERP preview, slug generator, UTM builder, and FAQ schema generator all run in the browser.